/*
 * Copyright (c) 2015, ARM Limited and Contributors. All rights reserved.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

#include <arch.h>
#include <arch_helpers.h>
#include <assert.h>
#include <bl_common.h>
#include <context_mgmt.h>
#include <debug.h>
#include <errno.h>
#include <tegra_private.h>

#define NS_SWITCH_AARCH32    1
#define SCR_RW_BITPOS        __builtin_ctz(SCR_RW_BIT)

/*******************************************************************************
 * Tegra132 SiP SMCs
 ******************************************************************************/
#define TEGRA_SIP_AARCH_SWITCH            0x82000004

/*******************************************************************************
 * SPSR settings for AARCH32/AARCH64 modes
 ******************************************************************************/
#define SPSR32        SPSR_MODE32(MODE32_svc, SPSR_T_ARM, SPSR_E_LITTLE, \
            DAIF_FIQ_BIT | DAIF_IRQ_BIT | DAIF_ABT_BIT)
#define SPSR64        SPSR_64(MODE_EL2, MODE_SP_ELX, DISABLE_ALL_EXCEPTIONS)

/*******************************************************************************
 * This function is responsible for handling all T132 SiP calls
 ******************************************************************************/
int plat_sip_handler(uint32_t smc_fid,
             uint64_t x1,
             uint64_t x2,
             uint64_t x3,
             uint64_t x4,
             void *cookie,
             void *handle,
             uint64_t flags)
{
    switch (smc_fid) {

    case TEGRA_SIP_AARCH_SWITCH:

        /* clean up the high bits */
        x1 = (uint32_t)x1;
        x2 = (uint32_t)x2;

        if (!x1 || x2 > NS_SWITCH_AARCH32) {
            ERROR("%s: invalid parameters\n", __func__);
            return -EINVAL;
        }

        /* x1 = ns entry point */
        cm_set_elr_spsr_el3(NON_SECURE, x1,
            (x2 == NS_SWITCH_AARCH32) ? SPSR32 : SPSR64);

        /* switch NS world mode */
        cm_write_scr_el3_bit(NON_SECURE, SCR_RW_BITPOS, !x2);

        INFO("CPU switched to AARCH%s mode\n",
            (x2 == NS_SWITCH_AARCH32) ? "32" : "64");
        return 0;

    default:
        ERROR("%s: unhandled SMC (0x%x)\n", __func__, smc_fid);
        break;
    }

    return -ENOTSUP;
}
